fixup! [ValueTracking] Compute known FPClass from dominating condition

Author: dtcxzyw

llvm/lib/Analysis/ValueTracking.cpp

@@ -4231,17 +4231,14 @@ static void computeKnownFPClassFromCond(const Value *V, Value *Cond,
                                         KnownFPClass &KnownFromContext) {
   CmpInst::Predicate Pred;
   Value *LHS;
-  Value *RHS;
   uint64_t ClassVal = 0;
+  const APFloat *CRHS;
   // TODO: handle sign-bit check idiom
-  if (match(Cond, m_FCmp(Pred, m_Value(LHS), m_Value(RHS)))) {
-    const APFloat *CRHS;
-    if (match(RHS, m_APFloat(CRHS))) {
-      auto [CmpVal, MaskIfTrue, MaskIfFalse] = fcmpImpliesClass(
-          Pred, *CxtI->getParent()->getParent(), LHS, *CRHS, LHS != V);
-      if (CmpVal == V)
-        KnownFromContext.knownNot(~(CondIsTrue ? MaskIfTrue : MaskIfFalse));
-    }
+  if (match(Cond, m_FCmp(Pred, m_Value(LHS), m_APFloat(CRHS)))) {
+    auto [CmpVal, MaskIfTrue, MaskIfFalse] = fcmpImpliesClass(
+        Pred, *CxtI->getParent()->getParent(), LHS, *CRHS, LHS != V);
+    if (CmpVal == V)
+      KnownFromContext.knownNot(~(CondIsTrue ? MaskIfTrue : MaskIfFalse));
   } else if (match(Cond, m_Intrinsic<Intrinsic::is_fpclass>(
                              m_Value(LHS), m_ConstantInt(ClassVal)))) {
     FPClassTest Mask = static_cast<FPClassTest>(ClassVal);

llvm/test/Transforms/InstCombine/fpclass-from-dom-cond.ll

@@ -134,8 +134,7 @@ define i1 @test6(double %x) {
 ; CHECK-NEXT:    [[CMP:%.*]] = fcmp ogt double [[X]], 0.000000e+00
 ; CHECK-NEXT:    br i1 [[CMP]], label [[LAND_RHS:%.*]], label [[LAND_END:%.*]]
 ; CHECK:       land.rhs:
-; CHECK-NEXT:    [[AND_I:%.*]] = bitcast double [[X]] to i64
-; CHECK-NEXT:    [[CMP_I:%.*]] = icmp eq i64 [[AND_I]], 9218868437227405312
+; CHECK-NEXT:    [[CMP_I:%.*]] = fcmp oeq double [[X]], 0x7FF0000000000000
 ; CHECK-NEXT:    br label [[LAND_END]]
 ; CHECK:       land.end:
 ; CHECK-NEXT:    [[RET:%.*]] = phi i1 [ false, [[ENTRY:%.*]] ], [ [[CMP_I]], [[LAND_RHS]] ]